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通过紫外-可见吸收光谱研究了环状二卟啉与trans-2,trans-3,trans-4和e型4种吡咯烷二取代C60衍生物(bis-C60)异构体之间的弱相互作用。研究表明,吡咯烷取代基团的引入使富勒烯与二卟啉的结合常数按C60单取代C60二取代C60的顺序降低。4种bis-C60与二卟啉的结合常数变化顺序为trans-2trans-3≈trans-4e,表明2个取代基间的相对位置对二取代C60与环状二卟啉间作用有一定影响,分析认为主、客体分子间空间位阻效应的差异是导致这一变化的主要原因。以trans-3 bis-C60/二卟啉复合物为代表,通过密度泛函理论模拟了其几何结构和吸收光谱。 相似文献
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TATP-铜(II)-L-丝氨酸(L-精氨酸)配合物与DNA的相互作用 总被引:1,自引:0,他引:1
采用电子吸收光谱、荧光光谱、粘度测定和琼脂糖凝胶电泳方法研究了配合物[Cu(TATP)(L-Ser)(H2O)]·ClO4(1)和[Cu(TATP)(L-Arg)(H2O)]2ClO4·0.5H2O(2)(TATP=1,4,8,9-四氮三联苯, L-Ser=L-丝氨酸, L-Arg=L-精氨酸)与DNA之间的相互作用. 结果表明, 配合物电子吸收光谱的最大吸收峰在加入DNA后产生明显的减色效应, 配合物能极大地淬灭溴化乙啶(EB)-DNA体系的荧光, DNA的粘度随配合物浓度的增加而增大, 表明配合物对DNA有较强的插入作用, 作用力大小为配合物2>1; 另外, 凝胶电泳实验结果表明配合物在维生素C存在的条件下对pBR322 DNA具有显著的断裂作用. 相似文献
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合成了meso-四(4-二茂铁甲酰氧基苯基)卟啉及其锌配合物.采用紫外-可见吸收光谱、稳态和时间分辨荧光光谱以及开孔Z-扫描等实验方法对其线性与非线性光学性质进行研究.结果表明二茂铁的引入对卟啉的吸收几乎未产生影响,但是却使卟啉的荧光发生了强烈的猝灭,荧光寿命缩短.说明在基态二茂铁与卟啉之间未发生作用,而在激发态发生了较强的电子和能量的传递.与相应的meso-四(4-苯甲酰氧基苯基)卟啉及其锌配合物相比,meso-四(4-二茂铁甲酰氧基苯基)卟啉及其锌配合物的反饱和吸收性能降低,但是非线性光学性质仍然优于性能优良的富勒烯C60. 相似文献
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水溶性四(p-磺酸钠苯基)金属卟啉配合物的合成、光谱性质及催化三氯苯酚的氧化脱氯反应 总被引:1,自引:0,他引:1
通过四苯基卟啉(H2TPP)和浓硫酸发生磺化反应及其金属化, 控制反应体系pH并利用透析法纯化, 高效合成了水溶性四(对磺酸钠苯基)卟啉(H2TPPS)及其金属配合物(FeTPPS和ZnTPPS); 采用UV-Vis、荧光、1H NMR和FTIR等光谱手段表征及研究了水溶性卟啉的结构及性质. 结果表明, 磺酸根离子的存在增强了卟啉分子间的π-π作用, 从而使H2TPPS及其金属配合物的分子间聚合作用增强. 研究了FeTPPS对2,4,6-三氯苯酚(TCP)催化氧化脱氯反应, 结果表明, FeTPPS/H2O2催化体系对TCP具备很好的催化氧化脱氯性能, 2,6-二氯对苯醌的转化数达到了766. 相似文献
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曙红与卟啉分子间和分子内的光致相互作用 总被引:1,自引:0,他引:1
合成了以半刚性链(一CH_2phCH_2—)和柔性链(—(CH_2)_4—)连接的曙红-卟啉二元化合物及其模型化合物.通过吸收光谱、荧光光谱、激发光谱及荧光寿命研究了模型化合物分子间的相互作用和二元化合物分子内的光致电子转移和能量传递.结果表明:二元化合物的模型化合物曙红乙酯和卟啉易形成基态复合物 在二元化合物分子内激发曙红时,曙红能将其单重态能量传递给卟啉,并能引发分子内的电子转移;激发卟啉时,能发生曙红向卟啉的电子转移.分析了分子构型和溶剂极性对2种过程的影响. 相似文献
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本文首次报道了μ-氧代双卟啉锰(Ⅲ)系列化合物对PhIO温和氧化环己烷反应的催化作用.与目前文献报道的其它类型卟啉相比,这些卟啉对环己烷单充氧反应具有更好的催化性能.动力学研究表明,卟啉环上取代基的特性常数与它们催化下的环己烷烃基化反应速率常数之间存在Hammett关系. 相似文献
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Four porphyrin-bridge-C60 dyads have been synthesized by covalently linking the chromophores at the opposite ends of a hydrogen bonded arylamide-derived foldamer bridge. For comparison, four C60-free porphyrin derivatives of the same frameworks have also been prepared. The fully hydrogen bonded bridges enable the appended porphyrin and C60 moieties to contact in a face-to-face manner. 1H NMR, UV-vis and fluorescent investigations in chloroform indicate that such a structural matching remarkably facilitates the intramolecular energy and electron transfer and charge separation between the two chromophores and also retards the recombination of the charge-separated state. Removing one hydrogen bond considerably reduces the energy and electron transfer. Further removing another one leads to no important interaction between the chromophores to occur. 相似文献
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Dr. Maria João Álvaro-Martins José Garcés-Garcés Dr. Antoine Scalabre Dr. Peizhao Liu Prof. Fernando Fernández-Lázaro Prof. Ángela Sastre-Santos Dr. Dario M. Bassani Dr. Reiko Oda 《Chemphyschem》2023,24(3):e202200573
The synthesis and characterization of diketopyrrolopyrroles and perylenemonoimidodiesters linked to a substituted benzoic acid in the ortho, meta, and para positions, are reported. Grafting of these dyes on the surface of chiral silica nanohelices is used to probe how the morphology of the platform at the mesoscopic level affects the induction of chiroptical properties onto achiral molecular chromophores. The grafted structures are weakly (diketopyrrolopyrroles) or strongly (perylenemonoimidodiesters) emissive, exhibiting both locally-excited state emission and a broad, structureless emission assigned to excimers. The dissymmetry factors obtained using circular dichroism highlight optimized supramolecular organization between the chromophores for enhancing the chiroptical properties of the system. In the ortho- derivatives, poor organization due to steric hindrance is reflected in a low density of chromophores on walls of the silica-nanostructures (<0.1 vs. >0.3 and up to 0.6 molecules/nm2 for the ortho and meta or para derivatives, respectively) and lower gabs values than in the other derivatives (gabs<2×10−5 vs 6×10−5 for the ortho and para derivatives, respectively). The para derivatives presented a better organization and increased values of gabs. All grafted chromophores evidence varying degrees of excimer emission which was not found to directly correlate to their grafting density. 相似文献
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《Electroanalysis》2006,18(9):841-848
Redox active films have been generated electrochemically by the reduction of dyads consisting of fullerene C60 covalently linked to zinc meso‐tetraphenyloporphyrin, ZnP? C60, and palladium acetate. The films are believed to consist of a polymeric network formed via covalent bonds between the palladium atoms and the fullerene moieties. In these films, the zinc porphyrin moiety is covalently linked to the polymeric chains through the pyrrolidine ring of the fullerene. The ZnP? C60/Pt films are electrochemically active in both positive and negative potential excursions. At positive potentials, two oxidation steps for the zinc porphyrin are observed. In the negative potential range, electron transfer processes involving the zinc porphyrin and the fullerene entities are observed. Film formation is also accompanied by palladium deposition on the electrode surface. The presence of a metallic phase in the film influences its morphology, structure and electrochemical properties. 相似文献
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Synthesis,Structure and Photophysical Properties of Ferrocenyl or Mixed Sandwich Cobaltocenyl Ester Linked meso‐Tetratolylporphyrin Dyads
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Sabapathi Gokulnath Balahoju Shivaprasad Achary Chakka Kiran Kumar Rajiv Trivedi Balasubramanian Sridhar Lingamallu Giribabu 《Photochemistry and photobiology》2015,91(1):33-41
We report here the design and synthesis of porphyrin–metallocene dyads consisting of a metallocene [either ferrocene or mixed sandwich η5‐[C5H4(COOH)]Co(η4‐C4Ph4) connected via an ester linkage at meso phenyl position of either free‐base or zinc porphyrin. All these dyad systems were characterized by various spectroscopic and electrochemical methods. A dimeric form of this molecule was observed in the X‐ray crystal structure of Zn‐TTPCo. The absorption spectra of all four dyads indicated the absence of electronic interactions between porphyrin macrocycle and metallocene in the ground state. However, interestingly, in all four dyads, fluorescence emission of the porphyrin was quenched (19–55%) as compared to their monomeric units. The quenching was more pronounced in ferrocene derivatives rather than cobaltocenyl derivatives. The emission quenching can be attributed to the excited‐state intramolecular photoinduced electron transfer from metallocene to singlet excited state of porphyrin and the electron‐transfer rates (kET) were established in the range 1.51 × 108 to 1.11 × 109 s?1. They were found to be solvent dependent. 相似文献
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A Supramolecular [10]CPP Junction Enables Efficient Electron Transfer in Modular Porphyrin–[10]CPP⊃Fullerene Complexes
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Youzhi Xu Bingzhe Wang Ramandeep Kaur Martin B. Minameyer Michael Bothe Prof. Dr. Thomas Drewello Prof. Dr. Dirk M. Guldi Prof. Dr. Max von Delius 《Angewandte Chemie (International ed. in English)》2018,57(36):11549-11553
Efficient photoinduced electron transfer was observed across a [10]cycloparaphenylene ([10]CPP) moiety that serves as a rigid non‐covalent bridge between a zinc porphyrin and a range of fullerenes. The preparation of iodo‐[10]CPP is the key to the synthesis of a porphyrin–[10]CPP conjugate, which binds C60, C70, (C60)2, and other fullerenes (KA>105 m ?1). Fluorescence and pump–probe spectroscopy revealed intramolecular energy transfer between CPP and porphyrin and also efficient charge separation between porphyrin and fullerenes, affording up to 0.5 μs lifetime charge‐separated states. The advantage of this approach towards electron donor–acceptor dyads is evident in the case of dumbbell‐shaped (C60)2, which gave intricate charge‐transfer behavior in 1:1 and 2:1 complexes. These results suggest that [10]CPP and its cross‐coupled derivatives could act as supramolecular mediators of charge transport in organic electronic devices. 相似文献
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Jean-Pascal Bourgeois Franois Diederich Luis Echegoyen Jean-Franois Nierengarten 《Helvetica chimica acta》1998,81(10):1835-1844
The synthesis of the cyclophane-type molecular dyads 1 and 1 . Zn was accomplished by Bingel macrocyclization of porphyrin-tethered bis-malonates 5 or 5 . Zn , respectively, with C60 (Scheme). In these macrocycles, the doubly bridged porphyrin adopts a close, tangential orientation relative to the surface of the C-sphere. The porphyrin derivatives 6 and 6 . Zn with two appended, singly-linked C60 moieties were also formed as side products in the Bingel macrocyclizations. The trans-1 addition pattern of the fullerene moiety in 1 and 1 . Zn was unambiguously established by 1H- and 13C-NMR spectroscopy. Due to the close spatial relationship between the fullerene and porphyrin components in 1 and 6 and the corresponding ZnII complexes, the porphyrin fluorescence is efficiently quenched as compared to the luminescence emitted by 5 and 5 . Zn , respectively (Fig. 2). Cyclic-voltammetry studies show that the mutual electronic effects exerted by the fullerene on the porphyrin and vice versa in 1 and 1 . Zn are relatively small despite the close proximity between the porphyrin donor and the fullerene acceptor (Fig. 3). 相似文献
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Highly Active and Robust Metalloporphyrin Catalysts for the Synthesis of Cyclic Carbonates from a Broad Range of Epoxides and Carbon Dioxide
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Dr. Chihiro Maeda Junta Shimonishi Ray Miyazaki Prof. Jun‐ya Hasegawa Prof. Tadashi Ema 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6556-6563
Bifunctional metalloporphyrins with quaternary ammonium bromides (nucleophiles) at the meta, para, or ortho positions of meso‐phenyl groups were synthesized as catalysts for the formation of cyclic carbonates from epoxides and carbon dioxide under solvent‐free conditions. The meta‐substituted catalysts exhibited high catalytic performance, whereas the para‐ and ortho‐substituted catalysts showed moderate and low activity, respectively. DFT calculations revealed the origin of the advantage of the meta‐substituted catalyst, which could use the flexible quaternary ammonium cation at the meta position to stabilize various anionic species generated during catalysis. A zinc(II) porphyrin with eight nucleophiles at the meta positions showed very high catalytic activity (turnover number (TON)=240 000 at 120 °C, turnover frequency (TOF)=31 500 h?1 at 170 °C) at an initial CO2 pressure of 1.7 MPa; catalyzed the reaction even at atmospheric CO2 pressure (balloon) at ambient temperature (20 °C); and was applicable to a broad range of substrates, including terminal and internal epoxides. 相似文献
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Davide Bonifazi Gianluca Accorsi Nicola Armaroli Fayi Song Amit Palkar Luis Echegoyen Markus Scholl Paul Seiler Bernhard Jaun Franois Diederich 《Helvetica chimica acta》2005,88(7):1839-1884
We report the synthesis and physical properties of novel fullerene–oligoporphyrin dyads. In these systems, the C‐spheres are singly linked to the terminal tetrapyrrolic macrocycles of rod‐like meso,meso‐linked or triply‐linked oligoporphyrin arrays. Monofullerene–mono(ZnII porphyrin) conjugate 3 was synthesized to establish a general protocol for the preparation of the target molecules (Scheme 1). The synthesis of the meso,meso‐linked oligopophyrin–bisfullerene conjugates 4 – 6 , extending in size up to 4.1 nm ( 6 ), was accomplished by functionalization (iodination followed by Suzuki cross‐coupling) of the two free meso‐positions in oligomers 21 – 23 (Schemes 2 and 3). The attractive interactions between a fullerene and a ZnII porphyrin chromophore in these dyads was quantified as ΔG=−3.3 kcal mol−1 by variable‐temperature (VT) 1H‐NMR spectroscopy (Table 1). As a result of this interaction, the C‐spheres adopt a close tangential orientation relative to the plane of the adjacent porphyrin nucleus, as was unambiguously established by 1H‐ and 13C‐NMR (Figs. 9 and 10), and UV/VIS spectroscopy (Figs. 13–15). The synthesis of triply‐linked diporphyrin–bis[60]fullerene conjugate 8 was accomplished by Bingel cyclopropanation of bis‐malonate 45 with two C60 molecules (Scheme 5). Contrary to the meso,meso‐linked systems 4 – 6 , only a weak chromophoric interaction was observed for 8 by UV/VIS spectroscopy (Fig. 16 and Table 2), and the 1H‐NMR spectra did not provide any evidence for distinct orientational preferences of the C‐spheres. Comprehensive steady‐state and time‐resolved UV/VIS absorption and emission studies demonstrated that the photophysical properties of 8 differ completely from those of 4 – 6 and the many other known porphyrin–fullerene dyads: photoexcitation of the methano[60]fullerene moieties results in quantitative sensitization of the lowest singlet level of the porphyrin tape, which is low‐lying and very short lived. The meso,meso‐linked oligoporphyrins exhibit 1O2 sensitization capability, whereas the triply‐fused systems are unable to sensitize the formation of 1O2 because of the low energy content of their lowest excited states (Fig. 18). Electrochemical investigations (Table 3, and Figs. 19 and 20) revealed that all oligoporphyrin arrays, with or without appended methano[60]fullerene moieties, have an exceptional multicharge storage capacity due to the large number of electrons that can be reversibly exchanged. Some of the ZnII porphyrins prepared in this study form infinite, one‐dimensional supramolecular networks in the solid state, in which the macrocycles interact with each other either through H‐bonding or metal ion coordination (Figs. 6 and 7). 相似文献
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Praseetha E. Kesavan Vijayalakshmi Pandey Masatoshi Ishida Hiroyuki Furuta Shigeki Mori Iti Gupta 《化学:亚洲杂志》2020,15(13):2015-2028
Beta‐pyrrole‐substituted porphyrin dyads connected by ethynyl linkage to N‐butylcarbazole or triphenylamine donors are reported. Donor‐π‐acceptor type beta‐substituted porphyrin dyads and their Zn(II) and Pd(II) complexes were characterized by MALDI‐MS, NMR, UV‐vis absorption, fluorescence and cyclic voltammetry techniques. The S1 emission dynamics were analyzed by time‐resolved spectroscopy (TCSPC); dyads exhibited efficient energy transfer up to 93% from beta‐donors (N‐butylcarbazole or triphenylamine group) to the porphyrin core. The efficiency of energy transfer for the beta‐substituted porphyrin dyads were much higher than those of the corresponding meso‐substituted porphyrin dyads, reflecting enhanced communications between the beta‐donors and the porphyrin core. The Pd(II) dyads, showed characteristic phosphorescence in the near IR region and very efficient singlet oxygen quantum yields (53–60%); these dyads are promising candidates for photocatalytic oxidations of organic compounds. The donor‐acceptor interaction between the porphyrin core and the beta‐donors was supported by the DFT studies in the porphyrin dyads. 相似文献
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M. B. Berezin N. M. Berezina M. I. Bazanov A. I. V’yugin A. S. Semeikin A. V. Glazunov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(8):1449-1451
The enthalpies of solution of 5,10,15,20-tetra(N-methylpyrid-4,3,2-yl)porphyrin tetraiodide were determined calorimetrically
at 298.15 K. Changes in the position of the heteroatom in the pyridyl fragment of the substituted porphyrin (meta- and ortho- positions) substantially decreased the endothermic effect of solution compared with the para- isomer. This was related to changes in the energy of the molecular crystal lattice, which decreased in the series para- > meta- > ortho-isomer. 相似文献